Vacuum excavation systems are known in the art of excavation. Particularly, for many years, utility companies and contractors have used vacuum excavation technology for accessing underground utility lines, such as gas lines, water lines, electric lines, sewer lines, etc. For most of those many years, the technology has experienced problems resultant from the material being handled. For example, clogged hoppers, poor filtration, inefficient dirt handling, equipment failure (often as a result of contamination by the dirt or other material being handled), and particularly the inability to handle water that may seep in the hole that is being evacuated, have plagued the art of vacuum excavation.
During the past year, Omega Tools and Keyspan Energy addressed one of these technical limitations by jointly developing a technology known as wet air digging system. This advancement has proven to have extensive advantages over conventional soil disturbances tools such as air lances and water jets. The xe2x80x9cwet airxe2x80x9d system is superior to conventional tools because is has the ability to disturb all types of soils at a rapid rate without possessing the inherent disadvantages of the conventional soil disturbance methods. Essentially, air knifes work well in porous soils producing dry excavated material for backfill (their advantage over water jets). However, they do not work well in non-porous soils such as clay. On the other hand, water jet systems disturb all forms of soil effectively (their advantage over air knifes) both excavated material is water soaked slop and as such is not usable for backfill. The wet air system possesses the advantages of both air knives and water jets without possessing any of their disadvantages.
The present invention is a fluid lance apparatus using a minimal amount of water droplets as an abrading medium, with compressed air as a primary medium. Upon excavation of the surface material, which can be asphalt, sod etc., dirt must be removed to provide access to an underground pipe. The tool of the present invention performs the task of disturbing earth or dirt by the use of high pressure air which propels water droplets into an underground hole, and in many cases to access an underground pipe without using equipment which may damage the pipe. The density of the water droplets, when added to the compressed air acts as a lance to disturb or xe2x80x9cbreak-upxe2x80x9d the dirt. The loosened dirt is then removed by vacuum. Furthermore, because the amount of water used in conjunction with compressed air is minimal, the hole can be refilled with the removed dirt, which, rather then comprising mud, is dry dirt.
Accordingly, it is the primary objective of this invention to provide a fluid lance tool which can disturb earth and other substances from an underground hole, wherein the fluid lance is comprised of compressed air means as a carrier medium and means providing minimal amount of water as an abrading medium, carried by the carrier medium.
It is a further object of the present invention to provide a tool which uses water droplets as an abrading material for removal of substances from the area around a utility to be repaired.
It is a further object of the present invention to provide a tool which uses a minimal amount of water so the hole can be refilled with dry dirt.
Other objects and advantages of the present invention will be readily understood upon a reading of the following brief description of the drawings figures, the detailed descriptions of the preferred embodiment and the appended claims.